Electric heater



FIG. 1 is a front perspective view of an electric heater showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof, the right view being a mirror image thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a bottom perspective view thereof.

The portions of the Figures shown in broken lines are shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an electric heater, as shown and described. 